This invention relates to drain filters and more particularly to a drain filter for use with a storm drain having a sump with an outflow pipe.
Many urban and suburban buildings have at least one storm drain located near their foundation. These storm drains are designed to remove excess water which flows around the base of the building during rain storms and snow melts, thereby preventing water damage. These drains generally consist of a concrete, mortar, brick or cement lined sump having a perforated metal storm drain cover. A drain pipe generally is located in the sump beneath the perforated cover, extending through a wall of the sump into a main building drainpipe. The main building drainpipe generally directs the flow of all water and waste materials passing through the building plumbing outwards into a sewer system.
At present, there is very little effective filtering of foreign objects from the water flowing through the sump. The storm drain cover is designed to filter any items which the water is carrying with it, such as leaves, twigs, paper, etc. However, any items smaller than the perforations in the storm drain cover will pass through those openings along with the flowing water. The heavier items will fall to the bottom of the sump and accumulate there. The lighter items tend to remain on the surface of the water in the sump, escape through the outflow pipe and flow into the building plumbing. The heavier items tend to clog the whole interior of the sump after a period of time and the lighter items tend to clog the drainpipe leading from the sump. The results of such clogging can include ground flooding and water damage to the building.
At present, in order to clean the storm drain, it is necessary to remove the storm drain cover and manually clean the interior of the sump. Any debris which has passed into the sump outflow pipe can only be removed with plumber's tools. If the debris has penetrated into the main plumbing and clogs the pipes, very expensive repairs would be required.
At present, the only apparatus for filtering debris from runoff water before it enters the storm drain sump consists of the perforated cover which rests upon the upper edge of the side walls of the sump. The Swaskey patent, U.S. Letters patent No. 4,045,346 discloses such a perforated storm cover and a non-filtering funnel tube there-beneath. There is no disclosure, however, of a method of filtering the water in the sump. The Cattano patent, U.S. Letters patent No. 3,986,958 discloses a filter for use in a swimming pool. The filter has inner and outer concentric filtering walls. These walls have differing densities and complimentary opening in their base. The openings in the base are controlled by a flapper valve. The base portion of the outer complimentary filter rests upon a stainless steel metallic support.
There currently is no storm drain filtering device which can be easily installed, effectively filter the incoming water, be easily removed from the storm drain sump and quickly cleaned or replaced; yet is also light in weight and capable of being used with storm drains having different interior dimensions.